Zayul County () or Zayü County () is a county in the Nyingchi Prefecture in the southeastern part of the Tibet Autonomous Region, China. The historical Zayul region is marked by the basin of the Zayul River, with its two branches: Rongto Chu (or the western Zayul River) and Zayul Chu (or the eastern Zayul River). The two branches join together near the town of Rima. After the junction, the Zayul river enters India's Arunachal Pradesh where it is called Lohit. The Zayul county borders India and Burma to the south and China's Yunnan province to the southeast. To the northeast lies the Pome County and to the northwest the Medog County. Its headquarters of the county is Kyigang, referred to as the Zayul Town . In 1950, Zayul County was the epicenter of a devastating earthquake. Geography Zayul County is located in an area of highly varying topography, lying just south of the Tibetan Plateau in the mountainous region east of the Himalayas where the Transhimalayas transition to the Hengduan Mountains. Specifically, the county straddles the southern parts of the Baxoila Range, the eastern parts of the Kangri Karpo mountains, and the eastern parts of the Mishmi Hills. Elevations generally decrease from northwest to southeast, with a maximal variation of : in the county, areas near the southern border have an elevation of , while there are 10 peaks over , the highest being Kawagarbo in the Meili Xue Shan at . The county has an average elevation of . The primary rivers are the Zayul River through the central parts of the county and Nu River (Salween) in the east. The county has an area of . Besides India, Burma, and Yunnan, it borders Zogang County to the north and Mêdog County to the southwest. Climate Owing to its moderate elevation (for Tibet), Zayul County has a subtropical highland climate (Köppen Cwb), a rarity in Tibet, with mild and quite dry winters, and warm, rainy summers. The rainy season lasts from March to September, and June through August each average more than 20 days of rainfall per month. The monthly daily average temperature ranges from in January to in July, and the annual mean is . The frost-free period is 280 days annually. Here, the diurnal temperature range is not large, maxing out at in November. Its climate is well-suited to support a variety of agricultural and forestry